I only got my iPhone on Monday (the day 6.0.2 was released I think) and I have about 2-4% drain per hour in standby with Wifi on (and in my house so it will connect), 3g and data on and bluetooth off.

Does this seem normal standby? I usually receive maybe 1 email or imessage an hour during these times and i don't really do anything (don't even unlock it).

Apples posted spec is 225hrs for standby. Therefore 100%/225=.44% per hour. If its only on standby and no apps running etc. So after 3 hrs you could expect to see 99%. Of course the meter is not linear so typically it may stay on 100% for a good while then drop off a little faster.

I am on 6.1B4 but a hunch is that IF apple changed the radio software to incorporate the WiFi fix, the engineers might have slipped in some bit if extra code for Mobile as well which is causing this blunder. And since it might be a small change, there was no need to mention in changelog.

There is a mobile feature called "Fast Dormancy" which basically tries to dial down to lower power mode when data is not being used on mobile networks which means if its enabled, the phone would have a quicker timeout to try and get down to 3G/H from H+ (for example). When disabled, this timeout is longer but the connection is much more stable.

The problem comes when the phone is forcing this strategy but the network doesnt support it at all (most countries at the moment) and this causes lot of data flickers and switching, thus draining battery more rapidly (especially in low signal areas).

As I said, its just my opinion since we cant actually look at the code.